style.css

html{   
    background-color: rgb(235, 126, 107);
}

html, body, #calcContainer, #calcContainer > *{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100%;
    width: 100%;
    box-sizing:border-box;
}

#calcContainer{
    height: 55%;
    width: 19%;
    border-radius: 20px;
    flex-direction: column;
    gap: 30px;
    padding: 25px;
    justify-content: flex-start;
    background-color: #393939;
}

#headerContainer{
    border-radius: 10px;
    height: 20%;
    width: 100%;
    background-color: #a4af77;
    justify-content: center;
    font-weight:bolder;
    padding: 15px;
    flex-direction: column;
}

#mainHeadCont{
    display: flex;
    height: 60%;
    width: 100%;
    background-color: #a4af77;
    /* border: 3px solid black; */
    justify-content:end;
    font-size: 26px;
}

#secHeadCont{
    display: flex;
    height: 40%;
    /* border: 3px solid black; */
    justify-content:end;
    font-size: 17px;
    width: 100%;
    background-color: #a4af77;
}

#bodyContainer{
    height: 80%;
    width: 100%;
    flex-wrap: wrap;
    gap: 5px;
    padding-bottom: 14.5px;
    padding-top: 14.5px;
}

button{
    background-color: #656568;
    color: white;
    font-weight: bolder;
    height: 16%;
    width: 22.75%;
    border-radius: 7.5px;
    border: none;
    font-family: 'Arial Black';font-size: 22px;
    transition: 0.2s;
}

button:hover{
    box-shadow: 0 8px 8px 0 rgba(0,0,0,0.24), 0 8px 8px 0 rgba(0,0,0,0.19);
    transform: translateY(-1.5px);
}

button:active, button.active{
    transform: translateY(1.5px);
    box-shadow: none;
}

.topBut{
    width: 48%;
    height: 18%;
    background-color: black;
    font-size: 16px
}

#equalBut{
    background-color: crimson;
}